Railway traffic controlling apparatus



Sept. 10, 1935. H. e. BLOSSER RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Jan. 4, 1934 [N VENT OR HIS A TTORNEY Herman 0. 310.9591 BY mw go 3w Patented Sept. .10, 1935 UNITED STATES PATENT OFFICE RAILWAY TRAFFIC CONTROLLING arrimn'rus Application January 4,

1934, Serial No. 705,277

My invention relates to railway trafiic controlling apparatus, and specifically to apparatus for controlling wayside, and/or cab signals by In the accompanying drawing, Fig. 1 is a" diagrammatic view showing one form of appara- 1') tus embodying my invention. Fig.2isadiagrammatic view showing a portion of the apparatus illustrated in Fig. 1, in greater detail. Referring to the drawing, I have shown a stretch of railway track divided by insulated rail ioints into track sections l--2 and 2-3, in which traflic normally moves from right to left, in the direction of the arrow. Each track section is I provided with a code-following direct current track relay designated by the reference character TR. with an exponent corresponding to the location. Each section is also provided with a battery B which supplies track circuit current for operating the associated track relay, and also a track transformer .T which supplies alternating rail current of any suitable frequency such for example as 60 or 100 cycles per second for controlling cab signaling apparatus. Since both alternating and direct current may flow simultaneously in the rails of a section, as explained hereinbelow, the track circuits of the section represent combined alternating and direct current loads and may be conveniently so termed. Considering the apparatus at location 3, which is representative of the apparatus at other wayside signal locations, the relay TR in following code, alternately closes front contact 4-5 and back contact l6. Each time that contact 4-5 closes, an impulse of current is received by relay A from a source having the terminals BC,

front contact 1. Relay A is of the usual quickpickup, quick-release type,'but due tothe presence of the rectifier RA whlchis poled in a direction such'as to provide a low resistance path for the current induced by the fiux decay in the relay core, relay A is capable of bridging the "off" tive resistance-temperature characteristic of the copper oxide rectifier RA' a resistor 32 is con-- nected in series therewith, for the .purpose'of masking orv compensating forv the resistance changes of the rectifier, in 0 er .to preserve a substantially uniform release-time for relay A,

which causes relay A to pick up and to close in spite of wide temperature variations. By constructing resistor 32 of material having apositive resistance-temperature coemcient, complete compensation for resistance changes with tempera-- ture in rectifier RA and the winding of relay A 5 can be obtained.

Each time that contact 4-6 of relay TR closes, relay H receives an impulse of current, over front contact 'l8 of relay A and relay H is maintained energized during the o code intervals by virtue of the rectifier EH which is poled in such manneras to make relay H slow re1easing.- No compensating resistor is required in series with rectifier EH because a greater variation in pickup and release time is permissible in the case of relay H than in the case of relay A If it be assumed for purposes of illustration that the codes used comprise rail current which is periodically interrupted at the rate of 180, 120, or times per minute, each of the tworelays A and H 20.

the auto-transformer type. As will be apparent '30 from an inspection of the drawing, when relay TM is operating, direct current will first flow through portion W of the auto-transformer winding in a given direction, and at the next moment will flow through portion W of the 35 winding in the opposite direction, thus causing a periodic reversal lot the flux in the core of trans-' former DT whereby an alternating voltage of -the code frequency will be induced in the autotransformer winding.

Decoding relay F is energized from a portion of the auto-transformer winding, through condenser C180, reactive transformer RTIBO, and rectifier RIM, and is selectively responsive to 180 code operation of the relay 'I'R because of-the electrical 45 tuning of the circuit of reactive transformer RT|80 by means of the condenser Clflfl. Slmilarly, relay E is energized from another portion of the auto-transformer winding and is selectively'responsive to code operation of relay TR. 50

' relays.

design, such for example as the oscillating pendulum type shown in United States Patent No. 1,858,876, granted on May-l7, 1932, .to Paul N. Bossart, for Coding apparatus. These code transmitters provide the 180, 120 and 80 codes by virtue of the operation of a code-following line relay CTR the energizing circuit of which is periodically interrupted over one or another of the contacts I80, I20, or 8!! of the respective code transmitter. The particular code which relay CTR is following at any given time depends on the traflic conditions in advance of section 23, as reflected in the condition of the decoding relays H E and F.

It will be noted that in the embodiment which is shown, direct current is supplied to the track circuits at all times, whereas alternating current is supplied to a particular track circuit during such time only as the given track circuit is occupied. That is, the track transformers which supply cab signaling energy become energized upon the. approach of a train. At location 3, relay V is the approach relay which, upon becoming deenergized due to the entry of a train into section 2-3, closes back contact Il-l3, thus connecting a source of alternating current having the terminals BX--CX, across the primary winding of transformer T The secondary winding of transformer T and the track battery B are connected in series across the two rails of section 2-3. The track feed conformer T at such times as approach relay V is deenergized. Contact I will operate at the rate of 180, 120 or 80 times per minute, depending.

upon traffic conditionsin advance, which conditions in turn determine which of the code transmitters CTI80, CTIZD, or CT88 will be effective in operating relay C'I'R v The apparatus shown at location 3 is duplicated at location I, as well as at any additional wayside signal locations along the stretch of track. Lo-

cation 2 represents a cut section, and since the code which is effective in section 2-3 is relayed or repeated into section l--2 over the contact l5|1 of the code-following track relay TR, no code transmitters and selective decoding equipment are required at location 2. Relay A is energized from the track battery B and remains energized as long as relay PR is either following code, or is energized in a direction such that front contact l5 -|6 is closed. Rectifier RA permits relay A to bridge the off" code intervals without at the same time materially affecting the quick pickup characteristic of the relay, and the resistor 33' provides for temperature compensation in the manner previously explained in connection with resistor 32. Condenser C is provided for the purpose of decreasing the arcing on contact l5l7 of relay TR.

Fig. 2 shows arelay which is described and claimed in my copending application Serial Number 705,278 filed January 4, 1934, for Electrical This relay is of the two-position, polarized type and comprises a field made up of two magnetizable portions 34, and a movable magnetizable armature 35, suitably pivoted at 33.

The armature 35 carries a contact l5 whichcw operates, respectively, with fixed contact Ii or IT, according as the armature occupies one or the other extreme position. The armature 35 is biased by a spring 31 in such manner that contact l5-l1 is maintained closed when the relay 5 is deenergized. The armature support 38 is made of magnetizable material'and is separated from the field members 34 by non-magnetizable spacers 39. A polarizing field is supplied by the permanent magnet 40. Obviously, thepolarizing field may be supplied in numerous other suitable ways, such as by a. winding, or by an electromagnet.

When winding I 8 is supplied with direct our- I rent of the proper polarity, the upper portion of armature 35 will develop a south pole and therefore, due to the polarizing action of magnet 40, armature 35 will be moved to the left, and will close contact l5l6, against the bias of spring 31. As soon'as current is removed from winding I8, the armature will be returned by spring 31 to the position illustrated. Should the current in winding I8 be reversed for any reason, contact l5l'| will be maintained closed, and the relay will be prevented from operating, by the combined effect of the pull of spring 31 and the magnetic torque of the relay.

The purpose in polarizing the track relays TR is to provide broken down insulated rail joint protection. It will be noted, with reference to the drawing, that the polarities of adjoining track 80 circuits are staggered. Therefore, should a pair of rail joints break down, permitting current from the adjoining track circuit to energize the track relay, the back-contacts of the relay will be held closed and the relay will be prevented 85 from following code, thus providing a restrictive indication as a warning of the fault.

Having described certain elements of the system individually, I shall now describe the operation of the system as a whole. When at least 40 three blocks in advance of location 3 are unoccupied, track relay TR will be following 180 code, as a, result of which, relays A H and F will be energized. Relay C'I'R will be operating on 180 code, over a circuit which includes contact 180 of code transmitter CTISB, wires I9 and 20, front point of contact 2| of relay F wire 22, front point of contact 23-of relay H andwire 24,- to relay CTR Since section 2-3 is unoccupied, relay A will be energized and front contact 25 of this relay will be closed. Therefore, relay V will be energized, and the terminal BX of the alternating current source will be disconnected from the primary winding of trans former T at back contact I ll3. v 65 Alternating current will, therefore, not be supplied to the rails of section 23. Direct current of 180 code will, however, be supplied to section 2-3 from battery B over front contact ll of relay CTR Since the secondary winding of transformer T is in series with the direct current source, a substantial fiux tends to be setup in the transformer core each time that contact l4 closes, with theresult that appreciable arcing tends to take place upon the opening of contact l4. To decrease ;the arcing, the primary winding of transformer T is short-circuited over front contact Ill2 of relay V The shortcircuited winding acts to retard the rate at which flux may build up 'in the core of transformer T and since the "on code periods are of relatively short duration, the value attained by the flux under the latter condition is substantially decreased, with a substantial improvement in the arcing condition. Obviously, it is not esential fr nt point of contact 21 of relay E wire 28,

cuited, as short circuiting any suitable winding on the transformer core will produce the result desired. a

When relay TR is following 180 code as described above, section 2-3 will be supplied with direct current of 180 code, and signal S which is controlled by the decoding relays H E and F in the usual and well-known manner, will provide an indication corresponding to clear trafilc conditions in three advance blocks. The

manner in which signal S is controlled by the b ck point of contact 2| of relay F wire 22, front point of contact 23 of relay H and wire 25, to relay CTRP. Signal S? will display an indication correspondingto two clear blocks in advance.

If the block in advance of location 3 is unoccupied, and the second block in advance is occupied, relay TR, will be following 80 code, and \relays A. and H will be energized, relays lit and 1 being both deenergized under this condition. Relay CTR will now be operating on 120 cod over a circuit which includes contact I20 of coii'e transmitter CTI20, wire 29, back point .of contact 21 of relay E wire 28, back point pied, relay 'I'R will be deenergized, and relays- A H, E and IF will all be deenergized. Due to the opening of front contact 9 of relay H all 'energywill be removed from the decoding transformer DT to economize current from the source 3-0 at such times as the decod ng equipment is not functioning. Relay CTR. will now 'with 180 code, relay TR? will follow this code,

. 15-11, into the rear section l-2.

- to the section in the rear of location I.

be operating on code, the energizing'circuit including contactall of, code transmitter CT80,

wire 30, back point of contact 23 of relay H and wire 24 to relay CTRF.

Considering now the operations at location and will repeat the code over back contact relay TR will follow and will repeat the and 80 codes which may be supplied to section 2-3.

Let it now be assumed that a train'which is moving from right to left enters section l-2,

the remaining sections which are shown being unoccupied. Track relay TR will become deenergized, causing all ofthe decoding relays A H E and F to release. Relay CTR! will follow 80 code, and will cause this code to'be supplied As soon as relay A releases, approach relay W will become'deenerg'ized vdue to the opening of front contact 25 of relay A Therefore, back contact ll-l3 of relay V will close, and since relay A is energized and its front contact 31 is closed when section 2-3 is unoccupied, the primary winding of transformer T? will be connected with Similarly,

the alternating currentsource BX-CX, and

coded cab signaling energy willbe supplied ahead of the train, in section i-2.

When the train enters section 2-3, relay 'I'R. will release, thus releasing relay A. As soon as front contact 3! of relay A opens, cab signaling current will be removed from section l-2. Also, the opening of front contact 25 of relay A will cause approach relay V to release and to apply cab signaling energy to section 2-3, ahead of the train". As soon as the train vacates section I-2, relay TR. remaining deenergized due to the continued presence of the train in section '2-3, steady direct current will be supplied to section |'-2, over the back contact IS-l1 of relay TR. Relay TR will, therefore, become steadily energized, and will pick up relay A over front contact 4-5. Approach relay V will now become energized over front contact 25 of relay A The use of steady direct current in section l-2, in

the manner described above, permits the clearing out of highway crossing apparatus or other detecting equipment by means of relay V should a highway crossing exist at a location such as 2.

As soon as the train 'vacates section 2-3, relay H being deenergized, relay' CTR will be op erated at 80 codeover contact 80 of code transmitter CT80 and the back point of contact 23 of relay H Section 2-3 will therefore be supplied with 80 code, and this code will be repeated into section l-2,in the manner previously explained. v Relay TR. will follow the 80 code, causing re'ays A and H to pick up, whereupon signal S will be operated to provide an indication that block l-3 is unoccupied, but that the block in advance of location 3 isoccupied. The remaining operations resulting from the passage of the train into other sections in advance of location 3 will be understood fromthe foregoing descript on without added explanation.

It will be noted that the code-current which is supplied to section 2-3 passes over a front. contact of relay CTR. whereas the code current supplied to section l-2 passes over a back 3 contact of relay TR. The reason for alternating front and back contacts of code-followof the release time to the pickup time of a track resistance due toweather conditions, the ratio relay is altered, since the ballast resistance has somewhat the effect of a snubbing resistor connected across the track relay terminals. The code-following line relays, as well as the track relays are subject to changes in the pickup-release time ratio with changes in temperature, and changes in other factors affecting relay ene erglzation throughout the section. Should it be required to repeat the code over a number of cut sections in cascade, the use .of front contacts or back contacts exclusively, for the code repetition, tends to result. in code distortion which is cumulative with each additional repeating relay,

being most pronounced in the'last section of the be obtained.

Obviously, where a number of cut sections are involved,.particularly if some or all of the sections are relatively short, it is not essential that strict alternation of code-feeding contacts of re-' lays in adjoining cut sections. be followed, as a .group. By alternating front and back contacts, substantial compensation for code distortion can substantially undistorted code may be obtained by alternating, for example, every third or every fourth section, or using any other combination of front and back contacts determined by the particular track circuit constants, which produces the least'amount of code distortion. Since the code supplied to code-following relays such as CTR and C'I'R at signal locations I and 3;"is always substantially true, being produced by the code transmitters CT80, CTIZO, and CTI80, and since relays C'I'R and CTR produce very little distortion, being unaffected by ballast conditions, therefore, the code supplied to the track rails at locations such as l and 3, is practically undistorted. For this reason, it does not matter, from the standpoint of code distortion, whether a front or a back contact of the CTR relay starts the code repetition for a group of cut sections.-

Although 'I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway track, a track transformer for at times supplying alternating signaling current to the rails of said section, a source of direct current included in the circuit of the secondary winding of said transformer for supplying direct signaling current to the railsof said section, a coding device, a contact controlled by said device for periodicallycoding the current supplied to the rails of said section, an approach relay, means controlled by said approach relay for at times energizing the pri-, mary winding of said transformer, and other means controlled by said approach relay for at other times short circuiting said primary winding to decrease arcing at said contact of the coding device.

2. In combination, a combined alternating and direct current load, a transformer having its secondary winding connected across said load,.a

source of direct current connected between said secondary winding and said load, a contact for interrupting the circuit of said load, means for attimes energizing the primary winding of said transformer, and means for at other times shortcircuiting said primary winding to decrease arcing at said contact when the circuit of said load is interrupted.

3. In combination, a combined alternating and direct current load, a transformer for supplying alternating current to said load, a source of direct current connected in series with said load, a contact for interruptingthe current of said lead,

means for at times energizing said transformer with alternating current to thereby energize said load, and means for at other times short/circuiting a winding of' said'transformer to decrease -arcing at said contact when the circuit of said.

load is interrupted.

- 4. In combination, a combined alternating and direct current load, a transformer for supplying alternating current to said load, a source of direct current connected in series with said load, a

contact for interrupting the current of said load,

means for attimes energizing said transformer with alternating current to thereby energize said load, and means for at other times decreasing the rate of flux change in-said transformer resulting from operation of said contact whereby arcing at said contact will be decreased.

5. In combination, a section of railway track, a track transformer connected across the two rails of said track for supplying alternating signaling current, a source of direct signaling current connected between said transformer and said track, a contact for interrupting the current supplied from said transformer and said direct current source to said track, means for at times supplying alternating current to said transformer to energize said track with alternating current, and means for at other times short circuiting a winding of said transformer to thereby decrease arcing at said contact.

6. In combination, a section of railway track, a track transformer connected across the two rails of said track, asource of direct current connected between said transformer and said track, a coding contact for interrupting the current from said transformer and said direct current source to said track, an approach relay, means including a back contact of said approach relay for energizing said transformerto supply alternating current to said track, and means including a front contact of said approach relay for short circuiting a winding of said transformer to decrease arcing at said coding contact.

'7. In combination, a load, a first and a second source of current connected in series across said load, said first source having a high inductance characteristic,- a contact for disconnecting said load from said two sources, means for rendering said first source eflective to supply current at given times only, and means effective at times other than said given times for decreasing the" 8'. In combination, a source of direct current,

an auto-transformer, means for periodically supplying direct current from said source to a portion of the winding of said auto-transformer whereby an alternating potential having a frequency d8". termined by the rate at which saiddirect current is supplied will be induced in theauto-transformer winding, atuned circuitcompris ing a reactive transformer and a condenser connected across a portion of said auto-transformer winding and tuned to resonance at a selected fre- 'quency of said induced potential, and control means governed by said tuned circuit in ac-- cordance with the frequency of said induced po-' 'tential.

-9. In combination, a source of direct current, an auto-transformer, means for periodically supplying direct current from said source to a portion of the winding vof-said auto-transformer. whereby an alternating potential having a frequency determined by the rate at which said direct current is suppliedwill be induced in the auto-transformer winding, a tuned circuit comprising a reactive transformer and a condenser i connected across a portion of said auto-transformer winding an'd'tuned to resonance at a selected frequency of said induced potential, and a control relay connected so as. to receive current from the output winding of said reactive transsource ofidirect current, an auto-transformer,"

means for periodically supplying direct current from said source to ,the winding of said autoto resonance at a selected frequency of said induced/potential, and a signal control relay connected so as to receive current from said tuned circuit and capable of attaining its energized condition when the frequency of said induced potential corresponds to the resonant frequency of said tuned circuit.

11. In combination, a source of direct current, an auto-transformer, means for establishing an alternating flux in the core of said auto-transformer by periodically supplying current from from the output winding of said reactive transformer through said rectifier and capable of attaining its energized condition whenthe frequency of said induced potential corresponds to the resonantfrequency of said tuned circuit.

12. In combination, a section of railway track, means for supplying said section with rail current of afirst or a second code accordance with traffic conditions in advance of said section, a code-following track relay for said section, a first relay having a release time capable of bridging the operation of .said track relay on said first or said second code, means including a front contact of said track relay for energizing said first relay, a second relay having a release time ca,- pable of bridging the operation of said track relay on said first or said second code, means in-, cluding a back contact of said track relay and a front contact of said first relay for energizing said second relay, a decoding relay controlled by said track relay in such manner as to become energized when and only when said track relay is following said second code, means controlled by said second relay for preventing the energize,- tion of said decoding relay, and traific governing means controlled by said second relay and said decoding relay.

13. In combination, a section of railway track, means for supplying said section with rail current of a first or a second code in accordance with trafl'lc conditionsv in advance of said section, a code-following track relay for said section, a first relay capable of bridging the code operation of said track relay on said first or said second code, means including a front contact of said track relay for energizing said first relay, 9. second relay capable of bridging the code operation of said track relay on said first or said second code, means including aback contact of said track relay and a front contact of said first relay for energizing said second relay, a decoding transformer which .becomes energized in response to code operation of said track relay, a decoding relay receiving energy from said transformer and selectively responsive to code operation of said track relay on said "second code,

means including a contact of said second relay for preventing the energization of said decoding transformer unless said second relay is energized, and trairlc governing means controlled by said second relay and said decoding relay.

14. In combination, a section of railway track, means for at times supplying coded rail current to said section, a code-following track relay for said section, a decoding transformer, a source of direct current, a circuit including a contact of 1 said track relay for periodically supplying direct current from said source to a winding of said decoding transformer, means effective for preventing the supply of direct current to said winding unless said track relay is following code, a 1 decoding relay controlled by the potential induced in said transformer when said winding is periodically supplied with direct current, and trafiic governing apparatus controlled by said decoding relay. ,2 15. In combination, a section of railway track, means for supplying said section with rail current of a first or a second code in accordance with trafiic conditions in advance'of saidsection, a code-following track relay for said section, a 2 first quick-pickup relay, a circuit including a front contact of said track relay for energizing said first relay, 2, rectifier connected across the winding of said. first relay for rendering said first relay sufficiently slow-releasing to bridge code 3 operation of said track relay on said first or said second code, means governed by said first relay for controlling the supply of train governing cur-1 rent to said section, a second quick-pickup relay, a circuit including a back contact of said track 3 'relay and a front contact of said first relay for -venting the energization of said decoding relay if said second relay is deenergized, and traffic governing means controlled by said second relay and said decoding relay.

16. In combination with a stretch of railways track divided into track circuit sections, a source of direct current for each of said sections and connected with the rails of each'section in'such manner as to provide staggered polarities in adjoining sections of said stretch, means for coding 5 the rail current supplied to said sections; a code following two position polarized track relay for each of said sections, said relay being biased to assume its reverse energized position at such times as current of normal relative polarity is not supplied to said relay, the track connections of said relay being reversed in adjoining track sections whereby, the relay will follow coded current supplied from said source to the respective section but will be prevented from operating by being held in its reverse energized position should rail current of the reverse relative polarity enter from an adjoining section into said relay; and trafiic'governing means controlled by said relay.

17. In combination with a stretch of railway manner as .to provide staggered polarities inadjoining sections of said stretch, means for coding the rail current'supplied to said sections; a distretch of track divided into track circuit sections, means for supplying coded direct current to each of said sections the polarity of the current being staggered in adjoining sections; and a codefollowing two-position polarized track relay'for each of said sections, said relay being mechanically biased to its reverseenergiz'edposition and having itstrack connections so arranged as to be capable of attaining its energized position only whenreceiving rail current from its associated seiition, whereby said relay will be caused to assume its reverse energized position should rail current from an adjoining section enter said relay.

19. In combination, .a first and a second section of railway track, means for supplying track current to each of said sections, a code-following line relay and a code-following track relay for said first. section, means including a front contact of said code-following line relay for coding the current supplied to said first section, means including a back contact of said code-following track relay for coding the current supplied to said second section, and traffic governing apparatus controlled by the code current supplied to said second section.

20. In a code system of signaling for a stretch of railway track divided into a plurality of cut sections, a code-following relay associated with each of said sections, and means for repeating the code supplied to a given cut section into the cut sections of said stretch in the rear of said given section, said means including alternate front and back code-repeating contacts of consecutive code-following relays to decrease code distortion resulting from changes in the pickuprelease timeratio of said-'code-following relays.

21. In a code system of signaling for a stretch of railway track divided into a plurality of cut sections, a code-followingrelay associated with each of said sections, and means for repeating the code supplied to a given cut section into the cut sections of said stretch in the rear of saidgiven section, said means including front contacts of code-following relays associated with the respective sections except that a back contact is 5 tortion which is permissible in said system.

22. In a code system of signalling for a stretch of railway track divided into a plurality of cut 5 sections, a code following relay associated with each of. said sections, and means for repeating the code supplied to a given out section into the cut sections of said stretch in the rear of said given section over a contact chain which includes front and back contacts of consecutive codefollowing relays associated with the respective sections, the selection of said front and back contacts forming consecutive elements of said chain being made in such manner as to substantially oifset the code distortion resulting from changes in the pickup-release time ratio of said codefollowing relays.

23. In combination with a stretch of railway track divided into track circuit sections; means for supplying coded direct current of a first or a second code to each of said sections in accordance with traflic conditions in advance, the polarity of said current being staggered in adjoining sections; a.two-position polarized code-following track relay for each of said sections having its track connections so arranged as to follow the codesupplied to its respective section, a repeating relay whichbecomes energized when said track relay is following said first or said second code, an auto-transformer, means including a contact of said track relay for periodically supplying direct current to said auto-transformer to induce an alternating potential in a winding thereof, a circuit including a. reactive transformer and a condenser energized from said winding and tuned for r'esponse'at the frequency of said second code,

a decoding relay energized from said tuned circuit, means including a contact of said repeating relay for preventing the supply of direct current to said auto-transformer, and traffic governing apparatus controlled by said repeating relay and said decoding relay. I

- HERMAN G. BLOSSER. 

